--- /dev/null
+/*
+ * STMicroelectronics TPM SPI Linux driver for TPM ST33ZP24
+ * Copyright (C) 2009 - 2015 STMicroelectronics
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/tpm.h>
+#include <linux/platform_data/st33zp24.h>
+
+#include "st33zp24.h"
+
+#define TPM_DATA_FIFO 0x24
+#define TPM_INTF_CAPABILITY 0x14
+
+#define TPM_DUMMY_BYTE 0x00
+
+#define MAX_SPI_LATENCY 15
+#define LOCALITY0 0
+
+#define ST33ZP24_OK 0x5A
+#define ST33ZP24_UNDEFINED_ERR 0x80
+#define ST33ZP24_BADLOCALITY 0x81
+#define ST33ZP24_TISREGISTER_UKNOWN 0x82
+#define ST33ZP24_LOCALITY_NOT_ACTIVATED 0x83
+#define ST33ZP24_HASH_END_BEFORE_HASH_START 0x84
+#define ST33ZP24_BAD_COMMAND_ORDER 0x85
+#define ST33ZP24_INCORECT_RECEIVED_LENGTH 0x86
+#define ST33ZP24_TPM_FIFO_OVERFLOW 0x89
+#define ST33ZP24_UNEXPECTED_READ_FIFO 0x8A
+#define ST33ZP24_UNEXPECTED_WRITE_FIFO 0x8B
+#define ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END 0x90
+#define ST33ZP24_DUMMY_BYTES 0x00
+
+/*
+ * TPM command can be up to 2048 byte, A TPM response can be up to
+ * 1024 byte.
+ * Between command and response, there are latency byte (up to 15
+ * usually on st33zp24 2 are enough).
+ *
+ * Overall when sending a command and expecting an answer we need if
+ * worst case:
+ * 2048 (for the TPM command) + 1024 (for the TPM answer). We need
+ * some latency byte before the answer is available (max 15).
+ * We have 2048 + 1024 + 15.
+ */
+#define ST33ZP24_SPI_BUFFER_SIZE (TPM_BUFSIZE + (TPM_BUFSIZE / 2) +\
+ MAX_SPI_LATENCY)
+
+
+struct st33zp24_spi_phy {
+ struct spi_device *spi_device;
+ struct spi_transfer spi_xfer;
+ u8 tx_buf[ST33ZP24_SPI_BUFFER_SIZE];
+ u8 rx_buf[ST33ZP24_SPI_BUFFER_SIZE];
+
+ int io_lpcpd;
+ int latency;
+};
+
+static int st33zp24_status_to_errno(u8 code)
+{
+ switch (code) {
+ case ST33ZP24_OK:
+ return 0;
+ case ST33ZP24_UNDEFINED_ERR:
+ case ST33ZP24_BADLOCALITY:
+ case ST33ZP24_TISREGISTER_UKNOWN:
+ case ST33ZP24_LOCALITY_NOT_ACTIVATED:
+ case ST33ZP24_HASH_END_BEFORE_HASH_START:
+ case ST33ZP24_BAD_COMMAND_ORDER:
+ case ST33ZP24_UNEXPECTED_READ_FIFO:
+ case ST33ZP24_UNEXPECTED_WRITE_FIFO:
+ case ST33ZP24_CMDRDY_SET_WHEN_PROCESSING_HASH_END:
+ return -EPROTO;
+ case ST33ZP24_INCORECT_RECEIVED_LENGTH:
+ case ST33ZP24_TPM_FIFO_OVERFLOW:
+ return -EMSGSIZE;
+ case ST33ZP24_DUMMY_BYTES:
+ return -ENOSYS;
+ }
+ return code;
+}
+
+/*
+ * st33zp24_spi_send
+ * Send byte to the TIS register according to the ST33ZP24 SPI protocol.
+ * @param: phy_id, the phy description
+ * @param: tpm_register, the tpm tis register where the data should be written
+ * @param: tpm_data, the tpm_data to write inside the tpm_register
+ * @param: tpm_size, The length of the data
+ * @return: should be zero if success else a negative error code.
+ */
+static int st33zp24_spi_send(void *phy_id, u8 tpm_register, u8 *tpm_data,
+ int tpm_size)
+{
+ u8 data = 0;
+ int total_length = 0, nbr_dummy_bytes = 0, ret = 0;
+ struct st33zp24_spi_phy *phy = phy_id;
+ struct spi_device *dev = phy->spi_device;
+ u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
+ u8 *rx_buf = phy->spi_xfer.rx_buf;
+
+ /* Pre-Header */
+ data = TPM_WRITE_DIRECTION | LOCALITY0;
+ memcpy(tx_buf + total_length, &data, sizeof(data));
+ total_length++;
+ data = tpm_register;
+ memcpy(tx_buf + total_length, &data, sizeof(data));
+ total_length++;
+
+ if (tpm_size > 0 && tpm_register == TPM_DATA_FIFO) {
+ tx_buf[total_length++] = tpm_size >> 8;
+ tx_buf[total_length++] = tpm_size;
+ }
+
+ memcpy(&tx_buf[total_length], tpm_data, tpm_size);
+ total_length += tpm_size;
+
+ nbr_dummy_bytes = phy->latency;
+ memset(&tx_buf[total_length], TPM_DUMMY_BYTE, nbr_dummy_bytes);
+
+ phy->spi_xfer.len = total_length + nbr_dummy_bytes;
+
+ ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
+ if (ret == 0)
+ ret = rx_buf[total_length + nbr_dummy_bytes - 1];
+
+ return st33zp24_status_to_errno(ret);
+} /* st33zp24_spi_send() */
+
+/*
+ * read8_recv
+ * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
+ * @param: phy_id, the phy description
+ * @param: tpm_register, the tpm tis register where the data should be read
+ * @param: tpm_data, the TPM response
+ * @param: tpm_size, tpm TPM response size to read.
+ * @return: should be zero if success else a negative error code.
+ */
+static int read8_reg(void *phy_id, u8 tpm_register, u8 *tpm_data, int tpm_size)
+{
+ u8 data = 0;
+ int total_length = 0, nbr_dummy_bytes, ret;
+ struct st33zp24_spi_phy *phy = phy_id;
+ struct spi_device *dev = phy->spi_device;
+ u8 *tx_buf = (u8 *)phy->spi_xfer.tx_buf;
+ u8 *rx_buf = phy->spi_xfer.rx_buf;
+
+ /* Pre-Header */
+ data = LOCALITY0;
+ memcpy(tx_buf + total_length, &data, sizeof(data));
+ total_length++;
+ data = tpm_register;
+ memcpy(tx_buf + total_length, &data, sizeof(data));
+ total_length++;
+
+ nbr_dummy_bytes = phy->latency;
+ memset(&tx_buf[total_length], TPM_DUMMY_BYTE,
+ nbr_dummy_bytes + tpm_size);
+
+ phy->spi_xfer.len = total_length + nbr_dummy_bytes + tpm_size;
+
+ /* header + status byte + size of the data + status byte */
+ ret = spi_sync_transfer(dev, &phy->spi_xfer, 1);
+ if (tpm_size > 0 && ret == 0) {
+ ret = rx_buf[total_length + nbr_dummy_bytes - 1];
+
+ memcpy(tpm_data, rx_buf + total_length + nbr_dummy_bytes,
+ tpm_size);
+ }
+
+ return ret;
+} /* read8_reg() */
+
+/*
+ * st33zp24_spi_recv
+ * Recv byte from the TIS register according to the ST33ZP24 SPI protocol.
+ * @param: phy_id, the phy description
+ * @param: tpm_register, the tpm tis register where the data should be read
+ * @param: tpm_data, the TPM response
+ * @param: tpm_size, tpm TPM response size to read.
+ * @return: number of byte read successfully: should be one if success.
+ */
+static int st33zp24_spi_recv(void *phy_id, u8 tpm_register, u8 *tpm_data,
+ int tpm_size)
+{
+ int ret;
+
+ ret = read8_reg(phy_id, tpm_register, tpm_data, tpm_size);
+ if (!st33zp24_status_to_errno(ret))
+ return tpm_size;
+ return ret;
+} /* st33zp24_spi_recv() */
+
+static int evaluate_latency(void *phy_id)
+{
+ struct st33zp24_spi_phy *phy = phy_id;
+ int latency = 1, status = 0;
+ u8 data = 0;
+
+ while (!status && latency < MAX_SPI_LATENCY) {
+ phy->latency = latency;
+ status = read8_reg(phy_id, TPM_INTF_CAPABILITY, &data, 1);
+ latency++;
+ }
+ return latency - 1;
+} /* evaluate_latency() */
+
+static const struct st33zp24_phy_ops spi_phy_ops = {
+ .send = st33zp24_spi_send,
+ .recv = st33zp24_spi_recv,
+};
+
+#ifdef CONFIG_OF
+static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
+{
+ struct device_node *pp;
+ struct spi_device *dev = phy->spi_device;
+ int gpio;
+ int ret;
+
+ pp = dev->dev.of_node;
+ if (!pp) {
+ dev_err(&dev->dev, "No platform data\n");
+ return -ENODEV;
+ }
+
+ /* Get GPIO from device tree */
+ gpio = of_get_named_gpio(pp, "lpcpd-gpios", 0);
+ if (gpio < 0) {
+ dev_err(&dev->dev,
+ "Failed to retrieve lpcpd-gpios from dts.\n");
+ phy->io_lpcpd = -1;
+ /*
+ * lpcpd pin is not specified. This is not an issue as
+ * power management can be also managed by TPM specific
+ * commands. So leave with a success status code.
+ */
+ return 0;
+ }
+ /* GPIO request and configuration */
+ ret = devm_gpio_request_one(&dev->dev, gpio,
+ GPIOF_OUT_INIT_HIGH, "TPM IO LPCPD");
+ if (ret) {
+ dev_err(&dev->dev, "Failed to request lpcpd pin\n");
+ return -ENODEV;
+ }
+ phy->io_lpcpd = gpio;
+
+ return 0;
+}
+#else
+static int tpm_stm_spi_of_request_resources(struct st33zp24_spi_phy *phy)
+{
+ return -ENODEV;
+}
+#endif
+
+static int tpm_stm_spi_request_resources(struct spi_device *dev,
+ struct st33zp24_spi_phy *phy)
+{
+ struct st33zp24_platform_data *pdata;
+ int ret;
+
+ pdata = dev->dev.platform_data;
+ if (!pdata) {
+ dev_err(&dev->dev, "No platform data\n");
+ return -ENODEV;
+ }
+
+ /* store for late use */
+ phy->io_lpcpd = pdata->io_lpcpd;
+
+ if (gpio_is_valid(pdata->io_lpcpd)) {
+ ret = devm_gpio_request_one(&dev->dev,
+ pdata->io_lpcpd, GPIOF_OUT_INIT_HIGH,
+ "TPM IO_LPCPD");
+ if (ret) {
+ dev_err(&dev->dev, "%s : reset gpio_request failed\n",
+ __FILE__);
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * tpm_st33_spi_probe initialize the TPM device
+ * @param: dev, the spi_device drescription (TPM SPI description).
+ * @return: 0 in case of success.
+ * or a negative value describing the error.
+ */
+static int
+tpm_st33_spi_probe(struct spi_device *dev)
+{
+ int ret;
+ struct st33zp24_platform_data *pdata;
+ struct st33zp24_spi_phy *phy;
+
+ /* Check SPI platform functionnalities */
+ if (!dev) {
+ pr_info("%s: dev is NULL. Device is not accessible.\n",
+ __func__);
+ return -ENODEV;
+ }
+
+ phy = devm_kzalloc(&dev->dev, sizeof(struct st33zp24_spi_phy),
+ GFP_KERNEL);
+ if (!phy)
+ return -ENOMEM;
+
+ phy->spi_device = dev;
+ pdata = dev->dev.platform_data;
+ if (!pdata && dev->dev.of_node) {
+ ret = tpm_stm_spi_of_request_resources(phy);
+ if (ret)
+ return ret;
+ } else if (pdata) {
+ ret = tpm_stm_spi_request_resources(dev, phy);
+ if (ret)
+ return ret;
+ }
+
+ phy->spi_xfer.tx_buf = phy->tx_buf;
+ phy->spi_xfer.rx_buf = phy->rx_buf;
+
+ phy->latency = evaluate_latency(phy);
+ if (phy->latency <= 0)
+ return -ENODEV;
+
+ return st33zp24_probe(phy, &spi_phy_ops, &dev->dev, dev->irq,
+ phy->io_lpcpd);
+}
+
+/*
+ * tpm_st33_spi_remove remove the TPM device
+ * @param: client, the spi_device drescription (TPM SPI description).
+ * @return: 0 in case of success.
+ */
+static int tpm_st33_spi_remove(struct spi_device *dev)
+{
+ struct tpm_chip *chip = spi_get_drvdata(dev);
+
+ return st33zp24_remove(chip);
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id of_st33zp24_spi_match[] = {
+ { .compatible = "st,st33zp24-spi", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, of_st33zp24_spi_match);
+#endif
+
+static SIMPLE_DEV_PM_OPS(st33zp24_spi_ops, st33zp24_pm_suspend,
+ st33zp24_pm_resume);
+
+static struct spi_driver tpm_st33_spi_driver = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = TPM_ST33_SPI,
+ .pm = &st33zp24_spi_ops,
+ .of_match_table = of_match_ptr(of_st33zp24_spi_match),
+ },
+ .probe = tpm_st33_spi_probe,
+ .remove = tpm_st33_spi_remove,
+};
+
+module_spi_driver(tpm_st33_spi_driver);
+
+MODULE_AUTHOR("TPM support (TPMsupport@list.st.com)");
+MODULE_DESCRIPTION("STM TPM 1.2 SPI ST33 Driver");
+MODULE_VERSION("1.3.0");
+MODULE_LICENSE("GPL");
projects / cascardo / linux.git / commitdiff